Cast as a gold-digging, scorned mistress desperate to promote a tell-all book and humiliate former lover Barry Bonds, Kimberly Bell pulled a shrewd maneuver on his defense team Monday.

Asked whether she had tried to "disparage Mr. Bonds in the most vulgar ways possible" on Howard Stern's radio show, Bell parried with lawyer Cristina Arguedas about what constituted vulgarity and then asked to have her memory of the show refreshed.

In other words, she wanted a transcript from the interview with Stern read to her and, by extension, into the record of Bonds' perjury and obstruction-of-justice trial. Arguedas went to the defense table and then returned to withdraw her question, saying: "We're going to decline that opportunity to go into the gutter."

Too late. Way too late.

The entire courtroom had passed the gutter hours earlier and spent most of the day in the sewer.

Bell's testimony was expected to be tawdry. The prosecution touted her as the witness who would validate that Bonds' testicles shrank and that he had experienced sexual dysfunction - both regarded as side effects of steroid use, about which Bonds is accused of lying in grand-jury testimony.

Both Bell and prosecutor Jeff Nedrow approached the sexual topics delicately, almost squeamishly. Arguedas cross-examined Bell so aggressively that the judge felt compelled to ask her to "ratchet down" her tone.

Reading from an e-mail that Bell sent to Bonds' website after their nine-year relationship ended in 2003, Arguedas rattled off Bell's descriptions of other women she believed were Bonds' lovers, including "the ugly whore in Vegas" and "the stripper in Arizona."

After that, Arguedas noted: "That's a lot of action" and "this is the man you described as having penile dysfunction." At the defense table, Bonds was spotted trying to hide a grin.

Some of the most unflattering testimony about Bonds at this trial has been elicited by his attorneys. Apparently, Arguedas earned her fee by defending Bonds' manhood and making Bell seem livid and bent on vengeance. The depiction of rampant womanizing was a necessary evil.

The strangest and most intriguing testimony of the day came when Bell explained how she thought of writing a book, which was not published but yielded title ideas of "In the Shadow of a Giant," "Giant Mistake" and "Bonds Girl."

"Liz told me I should write a book," Bell said, and she repeated it later.

By that, she meant Liz Watson Bonds, the second wife of the former left fielder. They married in 1998, 3 1/2 years into Bell's relationship with Bonds, and divorced last year. The book, however, was in the works as early as 2004, a year after Bell and Bonds broke up. (Or, as Bell described it, he "told me to disappear.")

So the wife and ex-mistress were somehow in cahoots? Later, Arguedas asked Bell how she felt about being demoted to road-trip girlfriend, because she once had been important enough to meet his parents. The attorney kept trying to draw Bell into acknowledging anger and resentment.

Instead, she and the jury got this from Bell: "I knew his wife, Liz, was getting it worse than I was."

For some reason, Arguedas did not ask her to elaborate.

Arguedas did ask Bell what Bonds had told her about "wife cities" and "girlfriend cities" for traveling ballplayers. She acknowledged that Bonds said a city like Miami is where players take their girlfriends. His colleagues in baseball should be really happy to hear that his trial dragged this into the light.

Asked about the fun of her road trips, Bell pointed out that Houston in 2001 did not end well. The terrorist attacks of Sept. 11 happened that week, and she said Bonds "abandoned" her as he took the team plane back to the Bay Area. Arguedas asked if it was true that no one but Giants personnel was ever allowed on the plane, and Bell curtly said there had been exceptions.

Arguedas repeatedly asked whether Bell started peddling information about steroid use to increase her visibility and push forward a book proposal. The defense attorney referred to the doping accusations as the book's "money shot," originally a term for a movie's big scene, now slang for a porn-flick climax.

The cringe factor wouldn't disappear. The leading candidate for lowest moment of the day might have been when Bell said that Bonds had threatened her in several ways, including vowing to "cut out my breast implants because he paid for them."

No one can say for sure how all of this went over with the jurors. But if they come into court today wearing HazMat suits, no one should be surprised.

Giants' Murphy on hat size

Mike Murphy, one of the original Giants employees when the team moved to San Francisco 53 years ago, testified briefly at Barry Bonds' perjury trial Monday.

Now the equipment manager for the team, Murphy was asked whether Bonds' hat size had changed after 1999, when he is alleged to have started using performance-enhancing drugs. Murphy said that he had to order a cap an eighth of an inch larger sometime between 2000 and 2002. The size, he said, went from 7 1/4 inches to 7 3/8 , even as Bonds began shaving his head.

Skull growth is believed to be a side effect of abusing human growth hormone.

On cross-examination, Murphy said both Willie Mays and Willie McCovey had required larger caps over time, but only after they retired and put on weight.

Asked whether he was nervous, Murphy drew laughter when he replied: "Oh, definitely."

Murphy is expected to be the only current team employee called to the stand.

Former team trainer Stan Conte, now with the Dodgers, is expected to appear today, possibly followed by former A's first baseman Jason Giambi.